Sustanon 250 or Sustamed (a trade name owned by Balkan Pharmaceuticals) is a blend of four esterified testosterone compounds:
- 30 mg testosterone propionate
- 60 mg testosterone phenylpropionate
- 60 mg testosterone isocaproate
- 100 mg testosterone decanoate
The numbers in the names refer to the fact that the content of testosterone compounds in each blend are 250 and 100 mg/ml, respectively.
The different testosterone esters provide for different half-lives. Esterization of the testosterone molecules provides for a sustained (but non-linear) release of testosterone hormone from the injection depot into the blood plasma.
While the intention of the mixed testosterone esters in Sustanon is to provide more stable serum testosterone levels, a single long-ester testosterone, such as testosterone cypionate or testosterone enanthate, may actually provide more stable serum testosterone levels